1. Field of the Invention
The present invention relates to an interchangeable part recognizing apparatus which recognizes a toner cartridge of a developing device used in an image forming apparatus such as a copier, facsimile or printer and a process cartridge removably formed on a main unit such as an image forming unit made by uniting part or the whole of an image forming apparatus, and an image forming apparatus which is equipped with the interchangeable part recognizing apparatus.
2. Description of the Related Art
In a main unit in which some parts are consumed when used, consumable articles are removably mounted to the main unit as interchangeable parts. For example, in an image forming apparatus such as a copier or a printer which consumes toner in an electrophotographic image forming process, a toner cartridge of a consumable article which contains toner is removably mounted as an interchangeable part at a predetermined position in the image forming apparatus of a main unit. In the case of being short of toner, the toner cartridge mounted to the image forming apparatus is replaced with a new toner cartridge, whereby toner is supplied.
In general, the kind of an interchangeable part such as a toner cartridge to be mounted is defined for every main unit such as an image forming apparatus. Interchangeable parts to be mounted are different when the manufacturers of main units are different, and there is a case where interchangeable parts to be mounted are different for every model even when the manufacturers of the main units are the same. In such a case, when a different kind of interchangeable part from an interchangeable part to be mounted is mounted to a main unit, the main unit does not work properly. Therefore, in order to maintain a proper working state of a main unit, a suitable kind of interchangeable part for the main unit needs to be mounted.
Thus, conventionally, a variety of configurations for judging whether an interchangeable part mounted to a main unit is suitable or not have been proposed. For example, Japanese Examined Patent Publication JP-B2 3-33512 (1991) discloses a configuration of disposing a mark for visually identifying a genuine part to the outer wall of a replenishing and interchanging part of office equipment, forming the mark with an electrode or a member subjected to a magnetic or optical process which can convert to electric signals, and disposing a plurality of detecting members which detect the electrode or the member subjected to a magnetic or optical process forming the mark to a main unit of the equipment, thereby causing the equipment to work only in the case where desired detection signals are obtained from the plurality of detecting members.
Further, Japanese Unexamined Patent Publication JP-A 2-61656 (1990) discloses a configuration of disposing an article display portion of a specific pattern to an interchangeable article and disposing a detecting device which detects the specific pattern of the article display portion of the interchangeable article to an apparatus to which the interchangeable article is mounted.
Furthermore, Japanese Examined Patent Publication JP-B2 2786764 discloses a configuration of three-dimensionally forming marks of a specific shape which are fitted in each other at a position of attaching a consumable part in a main unit and on an attachment surface of a consumable part, disposing an electric signal member which generates electric signals representing the kind of a consumable part to a side surface forming the outline of a mark of a consumable part, disposing a detecting member which detects electric signals generated by the electric signal member to a side surface forming the outline of the mark of the main unit, and disposing first storing means which stores electric signals for every kind of consumable part, second storing means which stores processing operations for a single kind of consumable part or plural kinds of consumable parts, searching means which searches electric signals from the first storing means, and processing operation reading out means which reads processing operations to be executed out of the second storing means, to the main unit.
However, the conventional configurations have such a problem that a mark and pattern of an interchangeable part mounted to a main unit cannot be detected accurately as a main unit is downsized and provided with a lot of functions and manufacturing work of interchangeable parts is simplified.
That is to say, although JP-B2 3-33512 and JP-A 2-61656 disclose a configuration of detecting a mark and pattern represented on an interchangeable part mounted to a main unit and disabling an operation of the main unit in the case where the detection result is not proper, these inventions do not disclose a configuration for detecting the mark and pattern more reliably and specific contents of information obtained from the result of detecting the mark and pattern. For this reason, in the case where the area of a mark and pattern is reduced as a main unit and an interchangeable part are downsized, it is impossible to distinguish the difference in the detection results due to the difference of marks and patterns from errors of the detection results. As a result, it cannot be accurately judged from the detection results whether a proper interchangeable part is mounted or not.
Further, since the invention disclosed in JP-B2 3-33512 and JP-A 2-61656 have a configuration of only detecting a mark and a pattern, the amount of information on an interchangeable part obtained from the detection result is little. For this reason, with an interchangeable part which becomes versatile as manufacturing work is simplified, in the case where the content of an operation in a main unit needs to be changed in accordance with the kind of interchangeable part, enough information to change the operation content cannot be obtained from the detection result. Therefore, the main unit automatically sets the content of an operation in accordance with a mounted interchangeable part, and an operation cannot be started immediately after replacement of an interchangeable part. This problem is caused not only in the case of using a versatile interchangeable part suitable for plural models of main units in such a case that a single toner cartridge can be mounted to plural models of copiers, but also in the case of using plural kinds of interchangeable parts in a single model of main unit in a case such that a plurality of toner cartridges containing different colors of toners can be mounted to a single copier.
On the other hand, since a mark and detecting means are three-dimensionally formed so as to be fitted in each other in the invention disclosed in JP-B2 2786764, manufacturing work is complicated, the manufacturing cost rises, and fitness of interchangeable parts is worse, with the result that a problem of poor practical utility is caused. Further, in the case of using capacitance as electric signals detected from a mark, it is difficult to strictly keep accuracy of thickness of a dielectric layer of a three-dimensional mark. Thus, there is a problem of raising the manufacturing cost and promoting decrease of practical utility.